Internally cooled rotor for rotary mechanism



April 6, 1965 F. P. SOLLINGER 3,176,916

INTERNALLY COOLED ROTOR FOR ROTARY MECHANISM Filed Nov. 20, 1962 3Sheets-Sheet l INVENTOR. FERDINAND F'. EIULLINEER ATTURNEY April 6, 1965F. P. SOLLINGER 3,175,916

INTERNALLY COOLED ROTOR FOR ROTARY MECHANISM Filed Nov. 20, 1962 3Sheets-Sheet 2 INVENTOR F ERDINAND F'. EULLINEEH ATTORNEY April 6, 1965F. P. SOLLINGER INTERNALLY COOLED ROTOR FOR ROTARY MECHANISM Filed Nov.20, 1962 3 SheetsSheet 5 ATTEIRNEY United States Patent 3,176,916INTERYALLY COOLED ROTOR FOR ROTARY RIECHANISM Ferdinand P. Sollinger,Wayne, N.J., assignor to Curtiss- Wright Corporation, a corporation ofDelaware Filed Nov. 20, 1962, Ser. No. 233,982 6 Claims. (Cl. 230210}This invention relates to rotary mechanisms such as fluid pumps, fiuidmotors, combustion engines or the like and more particularly to meansfor cooling the rotor in a rotary mechanism.

The invention is best understood when described with reference to arotary combustion engine and, although not limited to such use, is sodescribed herein. A rotary combustion engine as described herein may beof the type disclosed in United States Patent 2,988,065, issued on June13, 1961, to Felix Wankel et al.

The primary purpose of the invention is to provide a novel means foradequately cooling the interior of the rotor of a rotary mechanism witha minimum quantity of cooling medium such as lubricating oil. By keepingthe quantity of cooling oil within the rotor at a minimum, said oil doesnot materially affect the rotor counterbalancing requirements.

The invention is generally carried out by supplying relatively smallamounts of oil to one end face of the rotor where it enters openings atone end of a plurality of helical-like passageways formed in theinterior of the rotor and running from one end wall of the rotor to theother. Due to the inclination of the passages and the rotary motion ofthe rotor, the cooling oil is pumped from said one end of the passagesto their other ends at the opposite rotor end face from which the oildischarges into the space between the latter rotor end face and theadjacent end wall of the rotor housing from which the cooling oil drainsthrough a suitable drain passageway in the rotary mechanism. Because ofthe pumping action of the rotor and its inclined passageways, thecooling oil supplied to the rotor interior has a very short residencetime within the rotor interior and therefore greater heat transfer isobtained since the heated oil is carried quickly away and then replacedby fresh cooling oil. The present invention permits the rotor to run atsufiiciently cool metal temperatures with consequent reduction ofthermal distortion, reduction of deposits tending to stick the rotorseals and therefore improving seal operation. Another advantage of thepresent invention lies in the fact that a smaller oil pump may be usedsince the rotor runs with very little oil therein and because the rotoritself pumps the cooling oil therethrough. Therefore, overall engineweight will be reduced with consequent reduction in cost.

Accordingly, it is one object of the invention to provide a novel systemfor circulating a cooling medium through the interior of the rotor in arotary mechanism.

It is another object of the invention to provide a cooling system forthe interior of the rotor wherein a coolant is supplied at one end faceof the rotor and is circulated through a plurality of helical-likepassageways within the rotor interior with a relatively short residencetime therein and discharged from said passageways at the opposite endface of the rotor.

Another object of the invention is to provide a cooling system for theinterior of the rotor wherein the rotor interior has a plurality ofhelical-like passageways therein which aid in pumping the coolant fromone side of the rotor to the other.

It is additionally an object of the invention to provide a coolingsystem for the interior of the rotor wherein the coolant is circulatedin close proximity to the region of the rotor bearing the apex sealmembers.

3,1763% Patented Apr. 6, 1965 ice Other objects and advantages of theinvention will become apparent upon reading the following detaileddescription with the accompanying drawing in which:

FIG. 1 is a sectional view taken along line 1-1 of FIG. 2 showing arotary combustion engine embodying the present invention;

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a sectional view of the rotor taken along line 3-3 of FIG. 2,

FIG. 4 is a sectional view of the rotor itself taken along line 4-4 ofFIG. 2 with the rotor bearing sleeve shown in dot-dash outline.

In FIG. 1 there is shown a rotary combustion engine having an outer bodygenerally designated at 10. Although the engine of FIG. 1 is shownmounted with its shaft in a vertical position the invention is notlimited to vertically mounted engines and is equally applicable tohorizontally mounted engines. The outer body 10 is composed of aperipheral wall 12 interconnected with a pair of parallel spaced endwalls 14 and 16 by suitable means such as bolts 18. Suitable mountingbrackets, for example that shown at 17, may be provided on the end wall16 through which bolts (not shown) may pass to firmly support the enginein its vertical position. As shown in FIG. 2, the profile of the innersurface 13 of the outer body peripheral wall 12 preferably is basicallya two lobed epitrochoid. A shaft 29 is rotatably mounted in the outerbody It and has an eccentric portion 22 formed thereon upon which thereis rotatably mounted a rotor 24. A plain sleeve type bearing 26 issupported by the rotor 24, as will be explained in greater detail below,and serves to position the rotor on the eccentric portion 22. The outerperipheral wall 28 of the rotor 24 has a generally triangular profile toform three circumferentially-spaced apex portions 30 between each pairof which are defined working portions 31 (FIG. 2). Along each of theapex portions 30 there is provided an axial groove in which is mounted aradially movable seal strip 32 for sealing engagement with the innersurface 13 of the peripheral wall 12. Intermediate seal bodies 34 arealso provided on each end face of the rotor in sealing cooperation withthe apex seals 32 and end face seals 36 in the end faces of the rotor toprovide a continuous seal around working chambers 38a, 38b, and 330formed between the rotor and the outer body. The working chambers 38a,38b, and 38c vary in volume upon relative rotation of the outer body 10and rotor 24. Oil seals 40 may also be provided in each side face of therotor at a radially inward position thereof in order to prevent any oilleakage outwardly into the working chambers.

An internally-toothed gear 42 is secured to one side of the rotor 24, asillustrated in FIG. 1, and meshes with a fixed externally-toothed gear44 which is shrunk into the end wall 14, the fixed externally-toothedgear 44 hav ing an axially extending shank portion 46 which serves as abearing support for the shaft 20. The gears 42 and 44 serve to guide therotor 24 in tracing its epitrochoidal path. In the embodimentillustrated having a two-lobed epitrochoid and a three-lobed rotor theratio of rotation of the shaft with respect to the rotation of the rotoris 3:1 wherein for each rotation of the rotor about its axis, the shaftrotates three times about its axis.

As shown in FIG. 2, an intake port 48 is provided in one side of theperipheral wall for admitting air or a fuel-air mixture along with anexhaust port 50 for expelling the burnt gases from the outer body and onthe opposite side of the peripheral wall spark plug 52 is provided forigniting the fuel-air mixture which of course may be eliminated if theengine is run on diesel cycle. As the rotor 24 and outer body 10 rotaterelative to one -64 in the outer surface of said eccentric portion.

another the working fluid in the working'chambers undera liquid coolantto the interior of'the rotor 24. The

liquid coolant used in this case is a lubricating oil which serves tolubricate some of the moving parts of the engine as well as acting as acoolant for the interior of the rotor. The passageway 54 terminates inan annular groove 56 cut into the outer body end wall and surrounds theshaft 20, said annulus communicating with one end of .a passageway 58provided in the shaft 26} so that as the shaft rotates oil may be pumpedinto the shaft passageway 58. The passageway 58 communicates at itsother end witha radially extending passageway 59 and also with a shaftpassageway 62. The radial passageway 60 extends radially outwardly frompassageway 58 through the eccentric portion 22 and terminates in anopening An axiallyextending flat 66 or groove is cut into the outersurface of the eccentric and communicates with opening 64 in order thata portion of the oil may flow axially outwardly toward one endiface ofthe rotor, as will be explained in greaterdetail below. Alsocommunicating with opening 64 is an annular groove 68 cut out from theinner surface of bearing 26so that the oil will flow between theeccentric 22 and the bearing 26 in order to lubricate their engagingsurfaces. Some of this oil is also .used as the coolant for the interiorof the rotor as will also befurther explained below. a

The rotor 24 has a hollow construction such that its outer Wall consistsof end Wall portions 25 and 27 and a plurality of peripheral wallsections 28, each interconnecting a pair of adjacent apex portions 30 ofthe rotor. :The inner surface of the rotor outer wall has a plurality ofinwardly projecting spaced rib members 70 which extend from one end wallof the rotor to the other end wall in a direction inclined tothe rotoraxis. The rotor rib members 70 thereby have a helical-like configurationand form helical-like passageways 72 therebetween. The bearing sleeve 26is secured across the inner ends of the rib members 70 thereby formingthe inner walls of said helical-like passageways 72. The helical-likeconfiguration of the rib members 70 provides a strong and rigid supportfor the bearing sleeve 26.

Each of thepassageways 72 is open at each end to the space between theadjacent rotor end wall and the outer body end wall. For this purpose arecess is formed at each end of a rotor passageway in the adjacent rotorend wall and adjacent to the rotor bearing sleeve so that the recessesform supply openings 74 on one side of the rotor'and discharge openings76 on the oppositeside of the rotor' (FIG. 4.). 'When viewing thepassageways 72 toward their supply openings, it is apparent that thepassageways are inclined toward the direction of rotor rotation andviewedtoward their discharge openings, the passageways are inclinedopposite to the direction of rotor rotation as shown by the arrows ofFIGS. 3 and 4 which indicate the direction of rotor rotation. a

In FIGS. 3 and 4 it can be seen that in the apex .portions of the rotor,the rib members crossin a lattice-like fashion and the helicalpassageways 72 are continuous in this .region. Due to this constructionthe coolant may continuously flow through the continuous passageways.

With reference to the above-mentioned Patent through the passageway 54in end wall 16 into passage 7 way 58 and also around annulus 56 to theshaft passageway 58 as the shaft rotates. From the passageway 58 aportion of the oil will flow into shaft passageway 62 where it will flowbetween the shank portion 46 of the gear 44 and shaft 20 to lubricatethe bearing surfaces therebetween. Another portion of the oil from shaftpassageway 58 will flow radially outwardly through the radial passagewayoil in the eccentric 22 where some of this oil will flow into theannulus 68 in the bearing 26 to lubricate the bearing surfaces betweenthe bearing 26 and the eccentric 22, The remainder of the oil fromradial passageway Gtlwill flow into the axially extending fiat 66provided in the eccentric 22. where the oil will feed out into theregion on the gear side of the rotor between the eccentric and theadjacent rotor end wall 27. Due to the fact that the rotary motion ofthe rotor and shaft producesa loading and unloading elfect on thebearing surfaces of bearing 26 and shank portion 46 of gear 44, thesebearing surfaces will be slightly spread away from their respectivebearing surfaces on the eccentric 22 and shaft 2% on their unloadedside. Therefore, at these unloaded sides, the oil' supplied thereto mayflow axially outwardly from between the bearing surfaces where some ofthis oil will also discharge into the region between the eccentric andthe adjacent rotor end wall 27 on the gear side of the rotor.

' The rotary motion of the rotor produces centrifugal forces. Inresponse to these forces, the oil discharged between the eccentric andthe adjacent rotor end wall will'be thrown radially outwardly. Hence, asthe rotor rotates with respect to the shaft 20 and eccentric 22,

the openings 74 in each of the helical passageways 72 will besuccessively fed with the radially outwardly directed oil. With theorientation of the helical passageways 72 and the direction of rotationof the rotor 24, shown in FIG. 4 the oil upon entering the helicalpassageways 72 at the gear side end face of the rotor is relativelyrapidly pumped through the passageways to their opposite ends or to thedischarge openings 76 in each of the passageways 72 where the oil willbe discharged in a manner to be discussed more fully below.

At the location of the passageways in the region of the apex portions,the oil is pumped relatively close to the peripheralsurface of theseportions and, because these passageways are continuous in these regions,as shown inFIGS. 3 and 4, the oil is then pumped from the lobe portionof the rotor from which it entered the passageways 72 to an adjacentlobe portion from which it is then pumped to the openings '76.

As the rotor rotates, each point on the rotor traces an epitrochoidalpath and each point thereon has an acceleration force actong on it whichmay be shown to be at any instant the same as a force produced by therotor that would result from the rotational motion of the rotor about apoint which may be referred to as the instantaneous center ofacceleration of the rotor. It may be further shown that as the rotorrotates the direction of the acceieration force acting on any particularpoint on the rotor will periodically reverse so that at one instant theacceleration force may be directly radially outward and at the nextinstant the acceleration force will be directed radially inward.Reference may be made to copending application Serial No. 206,753, filedJuly 2, 1962, wherein the action of the acceleration forces acting onthe rotor is clearly described and illustrated.

As explained in said copending application, each partic le of oil withinthe rotor is subject to the same acceleratlon force as that acting on anadjacent wall portion of the rotor. So it can be seen, that as the oilenters the passageways 72 in the rotor 24 it will also be transferredthrough the rotor by the varying acceleration forces produced duringrotation of the rotor, as well asthe pumping act1on produced by theinclination of the passageways and relative direction of rotation of therotor, as described above. As the oil reaches the recessed openings 76at the opposite side of the rotor from which the oil was supplied, theacceleration forces acting radially inwardly at a particula instant ofrotor rotation will throw the oil out of said openings 76 and dischargethe oil into the region between the eccentric 22 and the adjacent rotorend wall 2:? where it may be collected and drained through a drainoutlet 78 in outer body end wall 16. The oil may then be recirculatedback through the pump (not shown) and used over again. Of course, itshould be realized that the invention is not limited to the oil supplymeans illustrated and any suitable oil supply means may be substitutedwhich will provide fresh cooling oil for the interior of the rotor.

So it can be seen that a system is provided which will supply a liquidcoolant to the interior of the rotor and the coolant will have arelatively short residence time in the rotor. The coolant is pumpedthrough the rotor by the rotary motion of the rotor itself and the novelcooling passageways provided therein. As the coolant flows through therotor, heat is transferred from the heated surfaces of the rotor to thecoolant which is quickly removed and then replaced by fresh coolant sothat the heat from the rotor walls is quickly carried away and the rotorwall temperature adequately stabilized. Further, it can be seen thatonly a relatively small amount of oil need be used to cool the rotorinterior and the amount of weight added due to the presence of the oilin the rotor is not significant and counterbalancing is not required.Also, due to the fact that only a relatively small amount of oil isused, a smaller oil pump may be used, than that in the case where therotor must be kept full of oil, which also adds to a total overallreduction in weight of the engine. Consequently, the costs of the enginewill be reduced and the performance made more efficient since weight isan important factor in combustion engine both from a cost andperformance standpoint.

While the invention has been specifically set forth in detail in theabove description the invention is not to be intended to be so limitedthereby and various modifications and alterations may be made by thoseskilled in the art without departing from the spirit and scope of theinvention defined in the following claims.

I claim:

1. In a rotary mechanism comprising an outer body having a cavitytherein, a rotatable shaft mounted in said outer body co-axial with saidcavity and having an eccentric portion thereon, a rotor journaled onsaid eccentric portion, said rotor having a multi-lobed peripheralsurface forming a plurality of circumferentially-spaced apex portionsfor sealing engagement with the inner peripheral surface of said outerbody thereby forming working chambers between the rotor peripheralsurface and the inner peripheral surface of said outer body which uponrelative rotation of said rotor and said outer body vary in volume, saidrotor having a hollow interior with a plurality of spaced ribsprojecting inwardly from the outer wall of the hollow rotor with each ofsaid ribs running from one end face of the rotor to the other in adirection inclined to the rotor axis to form separating walls of aplurality of open-end passageways inclined to the rotor axis, said rotoralso having an inner annular wall portion secured across said ribs toform the inner walls of said passageways; means for supplying a liquidcoolant to one end face of the rotor for flow of the coolant intoadjacent open ends of said rotor passageways, the inclination of saidrotor passageway separating walls being such, relative to the directionof rotor rotation, to function as a pump during rotor rotation to pumpthe liquid coolant through said rotor inclined passageways from said onerotor end face to the other rotor end face.

2. In a rotary mechanism as recited in claim 1 in which said rotorpassageways interconnect in the vicinity of each apex portion such thatthe liquid coolant upon being pumped through said passageways will flowin close proximity to the inner surface of each of said apex portions.

3. In a rotary mechanism as recited in claim 1 wherein said innerannular wall portion comprises a plain sleeve type bearing supported bysaid ribs.

4. In a rotary mechanism as recited in claim 1 wherein said means forsupplying a liquid coolant includes at least one coolant supplypassageway in said shaft, 21 radially-extending coolant supplypassageway in said ec centric portion communicating at one end with saidcoolant supply passageway in said shaft and at its opposite end with theouter surface of said eccentric portion and an axially extending coolantsupply passageway in said eccentric portion extending axially from saidradially-extending coolant supply passageway to the side of saideccentric portion adjacent to said one end face of the rotor.

5. In a rotary mechanism as recited in claim 4 wherein said innerannular wall portion comprises a plain sleeve type bearing supported bysaid rib members and said liquid coolant supply means further comprisesan annulus formed in the radially inner surface of said bearing incommunication with said radially-extending coolant supply passageway insaid eccentric portion so that a portion of said liquid coolant flowsout from between said bearing, and its shaft eccentric portion adjacentto said one end face of the rotor for flow therefrom into the adjacentopen ends of the rotor passageways.

6. A rotor for a rotary mechanism having an outer body defining a cavityand a rotatable shaft mounted in said outer body co-axial with saidcavity, said shaft having an eccentric portion thereon, said rotor beingjournaled on said shaft eccentric portion for rotation relative to saidouter body and said rotor being in sealing engagement with the innerperipheral surface of said outer body, and said rotor having a periheral wall interconnected with a pair of spaced end walls defining acavity, a plurality of spaced rib members projecting from the innersurface of said rotor peripheral wall definhrg a plurality of passageways therebetween, each of said rib members extending from a portion ofone end wall of said rotor to a portion of the opposite end wall of saidrotor circumferent-iallyspaced from the portion of said one end wall andsaid rib members forming the walls of a plurality of spaced liquidcoolant conducting passageways with each of said passageways having anopening in said one rotor end wall for receiving a liquid coolanttherein and an opening in said opposite rotor end wall for discharge ofsaid liquid cool ant from said passageway, and said rib members beingdisposed relative to the direction of rotation of said rotor such thatsaid rib members and said passageways function as a pump during rotationof said rotor to pump the liquid coolant from the opening in. said onerotor end wall to the discharge opening in said opposite rotor end wall.

1 References Cited by the Examiner UNITED STATES PATENTS 2,091,752 8/37Davis 230207 X 3,098,605 7/63 Bentele et a1. 230-207 X 3,102,683 9/63Paschke et al 230-207 X FOREIGN PATENTS 1, 120,481 12/ 61 Germany.

LAURENCE V. EFNER, Primary Examiner.

JOSEPH H. BRANSON, 1a., Examiner.

1. IN A ROTARY MECHANISM COMPRISING AN OUTER BODY HAVING A CAVITYTHEREIN, A ROTATABLE SHAFT MOUNTED IN SAID OUTER BODY CO-AXIAL WITH SAIDCAVITY AND HAVING AN ECCENTRIC PORTION THEREON, A ROTOR JOURNALED ONSAID ECCENTRI PORTION, SAID ROTOR HAVING A MULTI-LOBED PERIPHERALSURFACE FORMING A PLURALITY OF CIRCUMFERENTIALLY-SPACED APEX PORTIONSFOR SEALING ENGAGEMENT WITH THE INNER PERIPHERAL SURFACE OF SAID OUTERBODY THEREBY FORMING WORKING CHAMBERS BETWEEN THE ROTOR PERIPHERALSURFACE AND THE INNER PERIPHERAL SURFACE OF SAID OUTER BODY WHICH UPONRELATIVE ROTATION OF SAID ROTOR AND SAID OUTER BODY VARY IN VOLUME, SAIDROTOR HAVING A HOLLOW INTERIOR WITH A PLURALITY OF SPACED RIBSPROJECTING INWARDLY FROM THE OUTER WALL OF THE HOLLOW ROTOR WITH EACH OFSAID RIBS RUNNING FROM ONE END FACE OF THE ROTOR TO THE OTHER IN ADIRECTION INCLINED TO THE ROTOR AXIS TO FORM SEPARATING WALLS OF APLURALITY OF OPEN-END PASSAGEWAYS INCLINED TO THE ROTOR AXIS, SAID ROTORALSO HAVING AN INNER ANNULAR WALL PORTION SECURED ACROSS SAID RIBS TOFORM THE INNER WALLS OF SAID PASSAGEWAYS; MEANS FOR SUPPLYING A LIQUIDCOOLANT TO ONE END FACE O F THE ROTOR FOR FLOW OF THE COOLANT INTOADJACENT OPEN ENDS OF SAID ROTOR PASSAGEWAYS, THE INCLINATION OF SAIDROTOR PASSAGEWAY SEPARATING WALLS BEING SUCH, RELATIVE TO THE DIRECTIONOF ROTOR ROTATION, TO FUNCTION AS A PUMP DURING ROTOR ROTATION TO PUMPTHE LIQUID COOLANT THROUGH SAID ROTOR INCLINED PASSAGEWAYS FROM SAID ONEROTOR END FACE TO THE OTHER ROTOR END FACE.